The present invention relates to an improved tower for telecommunication signals, such as used for microwave, electromagnetic, light wave, television, etc.
Prior art telecommunication towers have generally been of an open grid structure with antennas mounted in fixed position at the top of the support. Such open structures have many disadvantages. They are difficult to maintain. They require cables to prevent excessive swaying due to wind and are open to adverse weather conditions. They are additionally susceptible to vandalism, especially the cutting of the cables securing the tower in place.
Such traditional lattice towers are generally considered to be unattractive and may devalue surrounding property as well as presenting a hazard to birds flying into the cable supports.
Lattice towers or monopoles present a particular problem when designing a multi-provider facility at one location. In such a system each antenna must be tailored in its orientation and direction to the requirements of each user. Due to the different orientations of the different providers systems, ie different azimuths (horizontal angular distances from a fixed reference direction), this typically requires the frames supporting the antennas to be turned in different directions on the tower to be set to the proper azimuths.
As time passes the system becomes over crowded. The antennas must be adjusted or replaced to accommodate new cell sites. This is a difficult task in such systems, often requiring cranes or similar units to reach the antenna sites and to permit the necessary modifications. In addition to the physical problems, change of equipment and antennas on the tower requires reanalysis of loads versus the original design specification in order to comply with building codes.
There has been some movement away from such lattice towers for use as a telecommunication facility. Substantially totally enclosed towers with architecturally pleasing exteriors have recently come into use. The outside appearance is that of a building, church tower or the like rather than that of a telecommunications tower. However, such units do not offer flexibility of rearranging antennas, ready access thereto, as well as the ability to handle multi-users with different orientations.
The basic concept of forming a communications tower out of prefabricated modular units is shown in U.S. Pat. No. 3,768,016 to Townsend et al. (1973). It is noted that in the Townsend et al. system their antennas A are mounted outside of the tower and thus are exposed to the elements. Access to the antennas requires descending from the tower roof to these outside locations--a rather dangerous operation.
The present invention is directed to overcoming the disadvantages of the preceding systems and to providing a particularly desirable multi-user antenna telecommunications tower.